Communication method, access point, and station

ABSTRACT

Embodiments of the present invention provide a method which includes: sending a first channel quality measurement report, wherein the first channel quality measurement report indicates a channel noise value measured in a first time period by a first station in a second antenna mode when a third station and a fourth station communicate with each other in a first antenna mode; and receiving an grant frame sent by the AP based on the first channel quality measurement report, wherein the grant frame carries first instruction information and/or second instruction information. A success rate of space-shared communication between station pairs can be increased.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/CN2016/1094794, filed on Dec. 12, 2016, which claims priority toChinese Patent Application No. 201610042129.8, filed on Jan. 22, 2016.The disclosures of the aforementioned applications are herebyincorporated by reference in their entireties.

TECHNICAL FIELD

Embodiments of the present invention relate to the communications field,and more specifically, to a communication method, an access point, and astation.

BACKGROUND

The Institute of Electrical and Electronics Engineers (IEEE) 802.11ad isa technology protocol specifying wireless local area network (WLAN)devices working on the 60 GHz frequency band, including a personal basicservice set (PBSS) control point (PCP)/access point (AP) and adirectional gigabit station (STA). Due to a characteristic of the 60 GHzfrequency band, a signal is subject to relatively serious loss andfading in the air. In a directional transmission system, when two STAscommunicate with each other, a sender interferes with another STA insystem space. Therefore, a plurality of STA pairs cannot communicatesimultaneously on a same frequency band to implement space-sharedcommunication.

In a mechanism of the existing IEEE 802.11ad protocol, in space, eachstation pair needs to first perform beamforming training to find atransmit antenna angle and/or a receive antenna angle suitable for both.This means only one fixed antenna mode is supported for communicationbetween two stations. During space sharing measurement, an access pointsequentially sends channel quality measurement requests to a pluralityof stations. As long as one of the plurality of STAs refuses to performchannel quality measurement or a channel noise value in a channelquality measurement report reported by one STA after channel measurementexceeds a threshold, the plurality of STAs cannot perform space-sharedcommunication.

However, in a next-generation protocol, if a multiple-inputmultiple-output (MIMO) technology is supported, which means a pluralityof antenna modes are supported between two stations, only one antennamode can be tried each time to perform space sharing measurement if theexisting space sharing method is used, resulting in a relatively lowsuccess rate of space-shared communication between station pairs.

SUMMARY

Embodiments of the present invention provide a communication method, toimprove a success rate of space-shared communication between stationpairs in one space sharing request process.

According to a first aspect, a communication method is provided. Themethod includes: receiving a first channel quality measurement reportsent by a first station and a second channel quality measurement reportsent by a second station, where the first channel quality measurementreport indicates a channel noise value measured in a first time periodby the first station in a second antenna mode when a third station and afourth station communicate with each other in a first antenna mode, andthe second channel quality measurement report indicates a channel noisevalue measured in the first time period by the second station in thesecond antenna mode when the third station and the fourth stationcommunicate with each other in the first antenna mode; and sending angrant frame if the channel noise value measured by at least one of thefirst station and the second station in the second antenna mode isgreater than a first threshold, where the grant frame carries firstinstruction information, and the first instruction information is usedto instruct to change the first antenna mode to an antenna mode otherthan the first antenna mode and/or to change the second antenna mode toan antenna mode other than the second antenna mode.

According to the communication method provided in this embodiment of thepresent invention, the channel noise value measured in the first timeperiod by the first station in the second antenna mode when the thirdstation and the fourth station communicate with each other in the firstantenna mode and the channel noise value measured in the first timeperiod by the second station in the second antenna mode when the thirdstation and the fourth station communicate with each other in the firstantenna mode, are received; and the grant frame is sent if the channelnoise value measured by at least one of the first station and the secondstation in the second antenna mode is greater than the first threshold,where the grant frame carries the first instruction information, and thefirst instruction information is used to instruct to change the firstantenna mode to an antenna mode other than the first antenna mode and/orto change the second antenna mode to an antenna mode other than thesecond antenna mode. In this way, a success rate of space-sharedcommunication between station pairs can be increased.

In one embodiment, the first instruction information is further used toindicate a second time period, and the method further includes:receiving a third channel quality measurement report sent by the firststation and a fourth channel quality measurement report sent by thesecond station, where the third channel quality measurement reportindicates a channel noise value measured in the second time period bythe first station in a current antenna mode when the third station andthe fourth station communicate with each other in the current antennamode, and the fourth channel quality measurement report indicates achannel noise value measured in the second time period by the secondstation in the current antenna mode when the third station and thefourth station communicate with each other in the current antenna mode;and sending second instruction information if the channel noise valuesmeasured by the first station and the second station in the currentantenna mode are both less than or equal to the first threshold, wherethe second instruction information is used to indicate a third timeperiod for the first station and the second station to communicate witheach other and a fourth time period for the third station and the fourthstation to communicate with each other, and the third time periodcompletely or partially overlaps the fourth time period, so that thefirst station, the second station, the third station, and the fourthstation perform space-shared communication.

In one embodiment, before the receiving a first channel qualitymeasurement report sent by a first station and a second station, themethod further includes: sending third instruction information to thefirst station and the second station among a plurality of stations,where the third instruction information is used to instruct the firststation and the second station to measure channel noise values in thefirst time period; and sending fourth instruction information to thethird station and the fourth station among the plurality of stations,where the fourth instruction information is used to instruct the thirdstation and the fourth station to communicate with each other in thefirst time period.

In one embodiment, before the sending third instruction information tothe first station and the second station among a plurality of stations,the method further includes: sending an antenna mode information requestto each of the plurality of stations, where the antenna mode informationrequest is used to request a quantity of antenna modes determined by thefirst station and the second station among the plurality of stationsthrough beamforming training, and a quantity of antenna modes determinedby the third station and the fourth station among the plurality ofstations through beamforming training.

In one embodiment, the third instruction information is carried in achannel quality measurement request frame, and the channel qualitymeasurement request frame is used to request to perform space sharingmeasurement; and after the sending third instruction information to thefirst station and the second station among a plurality of stations, themethod further includes: receiving channel quality measurementacknowledgement frames sent by the first station and the second station.

According to the communication method provided in this embodiment of thepresent invention, if a channel noise value in a channel qualitymeasurement report measured by at least one station in two station pairsexceeds a threshold, an antenna mode used by the at least one of the twostation pairs is directly changed and channel quality measurement isperformed again, with no need to send another channel qualitymeasurement request frame and receive a channel quality measurementacknowledgement frame sent by each station. This reduces signalingoverheads of communication between a station and an access point, andreduces a time required for a space sharing measurement process.

According to a second aspect, a commutation method is provided,including: sending, by a first station, a first channel qualitymeasurement report to an access point (AP), where the first channelquality measurement report indicates a channel noise value measured in afirst time period by the first station in a second antenna mode when athird station and a fourth station communicate with each other in afirst antenna mode; and receiving, by the first station, an grant framesent by the AP based on the first channel quality measurement report,where the grant frame carries first instruction information and/orsecond instruction information, the first instruction information isused to instruct the first station and the second station to measurechannel noise values in an antenna mode other than the second antennamode, and the second instruction information is used to instruct thefirst station and the second station to communicate with each other inan antenna mode other than the second antenna mode, so that the thirdstation and the fourth station measure channel noise values.

According to the communication method provided in this embodiment of thepresent invention, the first station sends the first channel qualitymeasurement report to the AP, where the first channel qualitymeasurement report indicates the channel noise value measured in thefirst time period by the first station in the second antenna mode whenthe third station and the fourth station communicate with each other inthe first antenna mode; and the first station receives the grant framesent by the AP based on the first channel quality measurement report,where the grant frame carries the first instruction information, and thefirst instruction information is used to instruct to change the secondantenna mode to the antenna mode other than the second antenna mode. Inthis way, a success rate of space-shared communication between stationpairs can be increased.

In one embodiment, the grant frame further carries third instructioninformation used to indicate a second time period, and the methodfurther includes: measuring, by the first station based on the thirdinstruction information, a channel noise value in the second time periodin a third antenna mode when the third station and the fourth stationcommunicate with each other in the first antenna mode; and sending, bythe first station, a second channel quality measurement report to theAP, where the second channel quality measurement report is used toindicate the channel noise value measured in the second time period inthe third antenna mode when the third station and the fourth stationcommunicate with each other in the first antenna mode.

In one embodiment, after the sending a second channel qualitymeasurement report to the AP, the method further includes: receiving, bythe first station, fourth instruction information sent by the AP basedon the second channel quality measurement report, where the fourthinstruction information is used to instruct the first station and thesecond station to communicate with each other in a third time period andthe third station and the fourth station to communicate with each otherin a fourth time period, and the third time period completely orpartially overlaps the fourth time period; and performing, by the firststation, space-shared communication with the second station, the thirdstation, and the fourth station based on the fourth instructioninformation.

In one embodiment, before the sending, by a first station, a firstchannel quality measurement report to an access point AP, the methodfurther includes: receiving, by the first station, an antenna modeinformation request sent by the AP, where the antenna mode informationrequest is used to request a quantity of antenna modes determined by thefirst station and the second station through beamforming training.

According to a third aspect, an access point is provided, configured toperform the method according to any one of the first aspect or thepossible implementations of the first aspect. Specifically, the accesspoint includes units configured to perform the method according to anyone of the first aspect or the possible implementations of the firstaspect.

According to a fourth aspect, a station is provided, configured toperform the method according to any one of the second aspect or thepossible implementations of the second aspect. Specifically, the stationincludes units configured to perform the method according to any one ofthe second aspect or the possible implementations of the second aspect.

According to a fifth aspect, an access point is provided, and the accesspoint includes a receiver, a transmitter, a memory, a processor, and abus system. The receiver, the transmitter, the memory, and the processorare connected by the bus system; the memory is configured to store aninstruction; the processor is configured to: execute the instructionstored in the memory, and control the transmitter to send a signal; andwhen the processor executes the instruction stored in the memory, theexecution causes the processor to perform the method according to anyone of the first aspect or the possible implementations of the firstaspect.

According to a sixth aspect, a station is provided, and the stationincludes a receiver, a transmitter, a memory, a processor, and a bussystem. The receiver, the transmitter, the memory, and the processor areconnected by the bus system; the memory is configured to store aninstruction; the processor is configured to: execute the instructionstored in the memory, and control the transmitter to send a signal; andwhen the processor executes the instruction stored in the memory, theexecution causes the processor to perform the method according to anyone of the second aspect or the possible implementations of the secondaspect.

According to a seventh aspect, a computer readable medium is provided,configured to store a computer program, where the computer programincludes an instruction used to perform the method according to any oneof the first aspect or the possible implementations of the first aspect.

According to an eighth aspect, a computer readable medium is provided,configured to store a computer program, where the computer programincludes an instruction used to perform the method according to any oneof the second aspect or the possible implementations of the secondaspect.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic flowchart of a communication method according toan embodiment of the present invention;

FIG. 2 is a schematic flowchart of another communication methodaccording to an embodiment of the present invention;

FIG. 3 is a schematic flowchart of another communication methodaccording to an embodiment of the present invention;

FIG. 4 is a schematic flowchart of another communication methodaccording to an embodiment of the present invention;

FIG. 5 is a schematic block diagram of a communications apparatusaccording to an embodiment of the present invention;

FIG. 6 is a schematic block diagram of another communications apparatusaccording to an embodiment of the present invention;

FIG. 7 is a schematic block diagram of still another communicationsapparatus according to an embodiment of the present invention; and

FIG. 8 is a schematic block diagram of still another communicationsapparatus according to an embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

The following describes the embodiments of the present invention withreference to the accompanying drawings in the embodiments of the presentinvention.

An access point (AP, Access Point), also referred to as a wirelessaccess point, a bridge, a hot spot, or the like, may access a server ora communications network. Optionally, the AP provided in the embodimentsof the present invention may be a device supporting the 802.11adstandard, and is backward compatible.

A station may be a wireless sensor, a wireless communications terminal,or a mobile terminal, for example, a mobile phone (or referred to as a“cellular” phone) supporting a WiFi communication function or a computerhaving a wireless communication function.

FIG. 1 shows a communication method 100 according to an embodiment ofthe present invention. The method 100 describes a schematic procedure ofspace-shared communication.

Operation S110. An access point sends a channel quality measurementrequest frame to a first station, a second station, a third station, anda fourth station.

Specifically, as shown in FIG. 2, the access point may send the channelquality measurement request frame to the first station, the secondstation, the third station, and the fourth station among a plurality ofstations. The channel quality measurement request frame is used torequest the first station, the second station, the third station, andthe fourth station to perform space sharing measurement.

In one embodiment, the access point may sequentially send the channelquality measurement request frame to the first station, the secondstation, the third station, and the fourth station, or maysimultaneously send the channel quality measurement request frame to thefirst station, the second station, the third station, and the fourthstation. This is not limited in this embodiment of the presentinvention.

It should be understood that, before operation S110, the first stationand the second station among the plurality of stations may obtain Mappropriate antenna modes through beamforming training, and the thirdstation and the fourth station may obtain N appropriate antenna modesthrough beamforming training, where an antenna mode used between thefirst station and the second station may be the same as or differentfrom an antenna mode used between the third station and the fourthstation, M≥1, N≥1, and M and N are not both 1.

It should also be understood that every two stations that have performedbeamforming training may store antenna modes obtained throughbeamforming training in respective memories of the stations, and alsostore an identifier of each antenna mode; or may store sequence numbersof antenna modes obtained through beamforming training and a mappingrelationship between each sequence number and a corresponding antennamode in respective memories of the stations. An identifier of an antennamode may be a sequence number of the antenna mode. This is not limitedin this embodiment of the present invention.

In one embodiment, it is assumed that the first station includes atransmit antenna a₁, a transmit antenna b₁, a receive antenna c₁, and areceive antenna d₁, and that the second station includes a transmitantenna a₂, a transmit antenna b₂, a receive antenna c₂, and a receiveantenna d₂. A first antenna mode is obtained through beamformingtraining. In the first antenna mode, when the first station sends asignal by using the second sector of the transmit antenna a₁, the secondstation receives the signal by using the third sector of the receiveantenna d₂; and when the second station sends a signal by using thesecond sector of the transmit antenna a₂, the first station receives thesignal by using the first sector of the transmit antenna b₁. Once anantenna mode between two stations has been determined, configurationinformation of a transmit antenna and a receive antenna used when thetwo stations communicate with each other can be determined. Optionally,an antenna mode between two stations may alternatively include a mode inwhich a plurality of transmit/receive antennas are used for signaltransmission. However, this embodiment of the present invention is notlimited thereto.

In one embodiment, the channel quality measurement request frame isfurther used to request a quantity of antenna modes determined by thefirst station and the second station among the plurality of stationsthrough beamforming training, and the channel quality measurementrequest frame sent to the third station and the channel qualitymeasurement request frame are further used to request a quantity ofantenna modes determined by the third station and the fourth stationthrough beamforming training.

Operation S121. The first station sends an acknowledgement(Acknowledgement, ACK) frame to the access point.

Operation S122. The second station sends an ACK frame to the accesspoint.

Operation S123. The third station sends an ACK frame to the accesspoint.

Operation S124. The fourth station sends an ACK frame to the accesspoint.

Specifically, as shown in FIG. 2, after receiving the channel qualitymeasurement request frame sent by the access point, the first station,the second station, the third station, and the fourth station may sendthe ACK frames to the access point. The ACK frames are used to indicatean agreement to space sharing measurement.

In one embodiment, the first station, the second station, the thirdstation, and the fourth station may sequentially send the ACK frames tothe access point when each station has received the channel qualitymeasurement request frame, or may simultaneously send the ACK frames tothe access point when all the stations have received the channel qualitymeasurement request frame. This is not limited in this embodiment of thepresent invention.

In one embodiment, the first station and the second station may add,into the ACK frames sent to the access point, the quantity of antennamodes determined through beamforming training, and the third station andthe fourth station may also add, into the ACK frames sent to the accesspoint, the quantity of antenna modes determined through beamformingtraining.

It should be understood that the access point receives a quantity ofantenna modes between every two stations, to manage and controlselection and change of an antenna mode between stations in subsequentscheduling. However, this embodiment of the present invention is notlimited thereto.

It should also be understood that two stations that have performedbeamforming training can pre-store a mapping table of antenna modes forcommunication with each other, and in a mapping table stored by eachstation, sequence numbers in ascending order may correspond to antennamodes with communication performance in descending order. When theaccess point performs scheduling, the stations may sequentially use theantenna modes in the mapping table that are corresponding to sequencenumbers in ascending order. To be specific, each station pairpreferentially uses an antenna mode with best communication performanceto perform communication, expecting to obtain, through channel qualitymeasurement, an antenna mode having best comprehensive communicationquality and performance for station pairs, so as to finally implementspace-shared communication between two station pairs. However, thisembodiment of the present invention is not limited thereto.

Operation S131. The access point sends first instruction information tothe third station and the fourth station among a plurality of stations,where the first instruction information is used to instruct the thirdstation and the fourth station to communicate with each other in a firsttime period.

Specifically, the access point may add, in operation S110, the firstinstruction information into the channel quality measurement requestframe sent to the third station and the fourth station. The firstinstruction information is used to instruct the third station and thefourth station to communicate with each other in the first time period.

Operation S132. The access point sends second instruction information tothe first station and the second station among the plurality ofstations, where the second instruction information is used to instructthe first station and the second station to communicate with each otherin a second time period.

Specifically, the access point may add, in operation S110, the secondinstruction information into the channel quality measurement requestframe sent to the first station and the second station. The secondinstruction information is used to instruct the first station and thesecond station to communicate with each other in the second time period.

Operation S141. The access point sends third instruction information tothe first station and the second station among the plurality ofstations, where the third instruction information is used to instructthe first station and the second station to measure channel noise valuesin the first time period.

Operation S142. The access point sends fourth instruction information tothe third station and the fourth station among the plurality ofstations, where the fourth instruction information is used to instructthe third station and the fourth station to measure channel noise valuesin the second time period.

Optionally, the access point may add the third instruction informationand the fourth instruction information into a broadcast frame, send thethird instruction information and the fourth instruction information toall stations in a broadcast manner, or send the third instructioninformation and the fourth instruction information in a multicast mannerto each station pair that has performed beamforming training. However,this embodiment of the present invention is not limited thereto.

Operation S151. In the first time period, the third station and thefourth station communicate with each other, and the first station andthe second station measure respective channel noise values.

Specifically, as shown in FIG. 2, in the first time period allocated bythe access point, the third station and the fourth station communicatewith each other in a first antenna mode; at the same time, the firststation and the second station set antennas to the first antenna mode,but do not perform communication; and the first station measures, byusing a receive antenna, the channel noise value existing in a channelin this time, and the second station measures, by using a receiveantenna, the channel noise value existing in a channel in this time.

In one embodiment, during the first time period, the third station andthe fourth station configure transmit and receive antennas based on thefirst antenna mode. The first time period may be divided into two equaltime segments. In the early half period of time, a transmit antenna ofthe third station may send a signal, and a receive antenna of the fourthstation may receive the signal sent by the third station. In the laterhalf period of time, the fourth station may send a signal, and a receiveantenna of the third station may receive the signal sent by the fourthstation. At the same time, when the third station sends the signal, thefirst station and the second station measure respective channel noisevalues in channels for subsequent channel quality measurement. However,this embodiment of the present invention is not limited thereto.

In one embodiment, a broadcast frame may be used to carry time segmentinformation of the first time period, such as a start time and durationof each time segment, and the broadcast frame may be further used tocarry an identifier of a transmit station and an identifier of a receivestation that are in each time segment. This is not limited in thisembodiment of the present invention.

Operation S152. In the second time period, the first station and thesecond station communicate with each other, and the third station andthe fourth station measure respective channel noise values.

This process is similar to operation S151. To avoid repetition, detailsare not described herein again.

Operation S161. The first station reports a measured channel noisevalue.

Operation S162. The second station reports a measured channel noisevalue.

Operation S163. The third station reports a measured channel noisevalue.

Operation S164. The fourth station reports a measured channel noisevalue.

Specifically, as shown in FIG. 2, the first station, the second station,the third station, and the fourth station may sequentially report thechannel noise values measured in each time period, or may simultaneouslyreport the channel noise values measured in each time period. This isnot limited in this embodiment of the present invention.

In one embodiment, if the channel noise values reported by the firststation, the second station, the third station, and the fourth stationare all less than or equal to a first threshold, it indicates that, whenthe first station and the second station communicate with each other,the third station and the fourth station may perform space-sharedcommunication on a same frequency band.

Operation S170. If the channel noise value received by the access pointand measured by at least one of the first station, the second station,the third station, and the fourth station is greater than the firstthreshold, the access point sends an grant frame to the first station,the second station, the third station, and the fourth station.

It should be understood that if the channel noise value measured by atleast one of the first station, the second station, the third station,and the fourth station is greater than the first threshold, it indicatesthat, when the third station and the fourth station communicate witheach other in a current antenna mode, interference of a sender of thethird station and the fourth station to communication between the firststation and the second station in a current antenna mode is excessivelylarge, or it indicates that, when the first station and the secondstation communicate with each other in a current antenna mode,interference of a sender of the first station and the second station tocommunication between the third station and the fourth station in acurrent antenna mode is excessively large. Therefore, space multiplexingcannot be implemented for the first station, the second station, thethird station, and the fourth station in a same time period on a samefrequency band to implement space-shared communication.

Specifically, as shown in FIG. 2, the grant frame carries fifthinstruction information, a third time period, and a fourth time period.The fifth instruction information is used to instruct to change thefirst antenna mode and/or a second communication mode. The third timeperiod is used for the first station and the second station to performchannel quality measurement and for the third station and the fourthstation to communicate with each other. The fourth time period is usedfor the third station and the fourth station to perform channel qualitymeasurement and for the first station and the second station tocommunicate with each other.

In one embodiment, it is assumed that before operation S170, the firststation and the second station use the first antenna mode, and the thirdstation and the fourth station use the second antenna mode. The accesspoint may instruct to change the first antenna mode to a third antennamode, may instruct to change the second antenna mode to a fourth antennamode, or may instruct to change the second antenna mode to a fourthantenna mode and change the first antenna mode to a third antenna mode.The first antenna mode may be the same as the second antenna mode, andthe third antenna mode may be the same as the fourth antenna mode. Thisis not limited in this embodiment of the present invention.

Operation S181. The third station and the fourth station communicatewith each other in a third time period in the current antenna mode, andat the same time, the first station and the second station measurerespective channel noise values.

Operation S182. The first station and the second station communicatewith each other in a fourth time period in the current antenna mode, andat the same time, the third station and the fourth station measurerespective channel noise values.

Specifically, as shown in FIG. 2, in the third time period and thefourth time period, channel quality measurement is performed. A specificprocess is similar to operation S151 and operation S152. To avoidrepetition, details are not described herein again.

Operation S191 to operation S194. The first station, the second station,the third station, and the fourth station report measured channel noisevalues.

Specifically, as shown in FIG. 2, a process of reporting measurementreports is similar to operation S161 to operation S164. To avoidrepetition, details are not described herein again.

Operation S210. If the channel noise values received by the access pointand reported by the first station, the second station, the thirdstation, and the fourth station are all less than or equal to the firstthreshold, the access point sends sixth instruction information to thefirst station and the second station, and sends seventh instructioninformation to the third station and the fourth station. The fifth timeperiod is used to instruct the first station and the second station tocommunicate with each other in a fifth time period, and the seventhinstruction information is used to instruct the third station and thefourth station to communicate with each other in a sixth time period.

Optionally, the sixth instruction information and the seventhinstruction information may be added into a beacon frame and sent to thefirst station, the second station, the third station, and the fourthstation in a broadcast manner. This is not limited in this embodiment ofthe present invention.

Specifically, if the channel noise values reported by the first station,the second station, the third station, and the fourth station to theaccess point are all less than or equal to the first threshold, itindicates that, when the first station and the second stationcommunicate with each other, the third station and the fourth stationmay perform space-shared communication on a same frequency band.

Operation S220. The first station and the second station communicatewith each other in the fifth time period in the current antenna mode,while the third station and the fourth station communicate with eachother in the sixth time period in the current antenna mode, to implementspace-shared communication.

According to the communication method provided in this embodiment of thepresent invention, the channel noise value measured in the first timeperiod by the first station in the second antenna mode when the thirdstation and the fourth station communicate with each other in the firstantenna mode and the channel noise value measured in the first timeperiod by the second station in the second antenna mode when the thirdstation and the fourth station communicate with each other in the firstantenna mode, are received; and the grant frame is sent if the channelnoise value measured by at least one of the first station and the secondstation in the second antenna mode is greater than the first threshold,where the grant frame carries the first instruction information, and thefirst instruction information is used to instruct to change the firstantenna mode to an antenna mode other than the first antenna mode and/orto change the second antenna mode to an antenna mode other than thesecond antenna mode.

According to the communication method provided in this embodiment of thepresent invention, if a channel noise value measured by a station doesnot meet a threshold requirement, the access point does not need to senda channel quality measurement request frame again, and the stations donot need to reply to the request frame. This reduces signaling overheadsof communication between the station and the access point, and reduces ameasurement time required for implementing space-shared communicationbetween station pairs.

FIG. 3 shows a communication method 300 according to an embodiment ofthe present invention. As shown in FIG. 3, the method 300 may beperformed by an AP.

Operation S310. Receive a first channel quality measurement report sentby a first station and a second channel quality measurement report sentby a second station, where the first channel quality measurement reportindicates a channel noise value measured in a first time period by thefirst station in a second antenna mode when a third station and a fourthstation communicate with each other in a first antenna mode, and thesecond channel quality measurement report indicates a channel noisevalue measured in the first time period by the second station in thesecond antenna mode when the third station and the fourth stationcommunicate with each other in the first antenna mode.

In one embodiment, the access point may receive the first channelquality measurement report sent by the first station, and the firstchannel quality measurement report indicates the channel noise valuemeasured in the first time period by the first station in the secondantenna mode when the third station and the fourth station communicatewith each other in the first antenna mode; and the access point mayfurther receive the second channel quality measurement report sent bythe second station, and the second channel quality measurement reportindicates the channel noise value received in the first time period bythe second station in the second antenna mode when the third station andthe fourth station communicate with each other in the first antennamode.

It should be understood that the third station and the fourth stationare two stations different from the first station and the secondstation, among a plurality of stations.

Operation S320. Send an grant frame if the channel noise value measuredby at least one of the first station and the second station in thesecond antenna mode is greater than a first threshold, where the grantframe carries first instruction information, and the first instructioninformation is used to instruct to change the first antenna mode to anantenna mode other than the first antenna mode and/or to change thesecond antenna mode to an antenna mode other than the second antennamode.

It should be understood that if the channel noise value measured by atleast one of the first station and the second station in the secondantenna mode is greater than the first threshold, it indicates thatinterference is excessively large when the first station, the secondstation, the third station, and the fourth station perform communicationsimultaneously in a same time period on a same frequency band, so thatspace-shared communication is not possible. Therefore, it is necessaryto change an antenna mode of at least one station pair and perform spacesharing measurement again.

In one embodiment, if the channel noise value measured by at least oneof the first station and the second station in the second antenna modeis greater than the first threshold, the access point may send the grantframe to the first station, the second station, the third station, andthe fourth station. The grant frame carries the first instructioninformation, and the first instruction information is used to instructthe first station and the second station to change the first antennamode to an antenna mode other than the first antenna mode and/orinstruct the third station and the fourth station to change the secondantenna mode to an antenna mode other than the second antenna mode.

In one embodiment, the grant frame further carries a second time periodfor the first station, the second station, the third station, and thefourth station to perform space sharing measurement again. After S320,the access point may receive a third channel quality measurement reportsent by the first station and a fourth channel quality measurementreport sent by the second station. The third channel quality measurementreport indicates a channel noise value measured in the second timeperiod by the first station in a current antenna mode when the thirdstation and the fourth station communicate with each other in a currentantenna mode, and the fourth channel quality measurement reportindicates a channel noise value measured in the second time period bythe second station in the current antenna mode when the third stationand the fourth station communicate with each other in the currentantenna mode.

In one embodiment, if the channel noise values received by the accesspoint and measured by the first station and the second station in thecurrent antenna mode are both less than or equal to the first threshold,the access point may send second instruction information to the firststation, the second station, the third station, and the fourth station.The second instruction information is used to indicate a third timeperiod for the first station and the second station to communicate witheach other and a fourth time period for the third station and the fourthstation to communicate with each other, and the third time periodcompletely or partially overlaps the fourth time period, so that thefirst station, the second station, the third station, and the fourthstation perform space-shared communication.

It should be understood that if the channel noise values received by theaccess point and measured by the first station and the second station inthe current antenna mode are both less than or equal to the firstthreshold, it indicates that the first station, the second station, thethird station, and the fourth station may simultaneously performcommunication in a same time period on a same frequency band.

In one embodiment, the access point may add the second instructioninformation into a beacon frame and send the second instructioninformation to the first station, the second station, the third station,and the fourth station in a broadcast manner, or may send the secondinstruction information in a multicast manner separately to the firststation and the second station and to the third station and the fourthstation. This is not limited in this embodiment of the presentinvention.

In one embodiment, before operation S310, the access point may sendthird instruction information to the first station and the secondstation among a plurality of stations, and the third instructioninformation is used to instruct the first station and the second stationto measure channel noise values in the first time period. Alternatively,the access point may send fourth instruction information to the thirdstation and the fourth station among the plurality of stations, and thefourth instruction information is used to instruct the third station andthe fourth station to communicate with each other in the first timeperiod.

Optionally, the access point may send, to the first station and thesecond station, a channel quality measurement request frame forrequesting to perform space sharing measurement and add the thirdinstruction information into the channel quality measurement requestframe sent to the first station and the second station. The access pointmay simultaneously send the channel quality measurement request frame tothe first station and the second station, or may sequentially send thechannel quality measurement request frame to the first station and thesecond station. This is not limited in this embodiment of the presentinvention.

In one embodiment, the access point may add the fourth instructioninformation into a broadcast frame sent to the third station and thefourth station, or may send the fourth instruction information to thethird station and the fourth station information in a multicast manner.This is not limited in this embodiment of the present invention.

It should be understood that the foregoing space sharing measurementprocedure is on the basis that the access point knows in advance thatthe first station and the second station can communicate with each otherin a plurality of antenna modes and that the third station and thefourth station can communicate with each other in a plurality of antennamodes.

Optionally, if the access point does not know, before space sharingmeasurement, a quantity of antenna modes supported between the firststation and the second station and a quantity of antenna modes supportedbetween the third station and the fourth station, the channel qualitymeasurement request frame sent by the access point to the first stationand the second station may be further used to request the quantity ofantenna modes obtained by the first station and the second stationthrough beamforming training.

According to the communication method provided in this embodiment of thepresent invention, a success rate of space-shared communication betweenstation pairs can be increased. If a channel noise value measured by astation does not meet a threshold requirement, the access point does notneed to send a channel quality measurement request frame again, and thestations do not need to reply to the request frame. This reducessignaling overheads of communication between the station and the accesspoint, and reduces a measurement time required for implementingspace-shared communication between station pairs.

FIG. 4 shows a communication method 400 according to an embodiment ofthe present invention. As shown in FIG. 4, the method 400 may beperformed by a station STA.

Operation S410. A first station sends a first channel qualitymeasurement report to an access point AP, where the first channelquality measurement report indicates a channel noise value measured in afirst time period by the first station in a second antenna mode when athird station and a fourth station communicate with each other in afirst antenna mode.

In one embodiment, the first station may send the first channel qualitymeasurement report to the AP, and the first channel quality measurementreport is used to report, to the AP, the channel noise value measured inthe first time period by the first station in the second antenna modewhen the third station and the fourth station communicate with eachother in the first antenna mode.

It should be understood that when the first station measures the channelnoise value, the first station configures antennas in the first antennamode obtained through beamforming training with the second station, tomeasure, in the first antenna mode, impact on the first station existingwhen another station sends a signal.

Operation S420. The first station receives an grant frame sent by the APbased on the first channel quality measurement report, where the grantframe carries first instruction information and/or second instructioninformation, the first instruction information is used to instruct thefirst station and the second station to measure channel noise values inan antenna mode other than the second antenna mode, and the secondinstruction information is used to instruct the first station and thesecond station to communicate with each other in an antenna mode otherthan the second antenna mode, so that the third station and the fourthstation measure channel noise values.

In one embodiment, the first station may receive the grant frame sent bythe AP based on the first channel quality measurement report. The grantframe may carry the first instruction information, and the firstinstruction information is used to instruct to change the first antennamode in which the first station and the second station measure thechannel noise values. The grant frame may further carry the secondinstruction information, and the second instruction information is usedto instruct to change the second antenna mode in which the first stationand the second station communicate with each other, so that the thirdstation and the fourth station measure the channel noise values.

In one embodiment, the grant frame may be sent to the first station andthe second station in a broadcast manner, or may be sent to the firststation and the second station in a multicast manner. This is notlimited in this embodiment of the present invention.

In one embodiment, the grant frame may further carry third instructioninformation, and the third instruction information is used to indicate asecond time period. The first station may measure a channel noise valuein the second time period in a third antenna mode based on the thirdinstruction information when the third station and the fourth stationcommunicate with each other in the first antenna mode. Then the firststation may send a second channel quality measurement report to the AP,and the second channel quality measurement report is used to indicatethe channel noise value measured in the second time period in the thirdantenna mode when the third station and the fourth station communicatewith each other in the first antenna mode.

In one embodiment, the first station may receive fourth instructioninformation sent by the AP based on the second channel qualitymeasurement report. The fourth instruction information is used toinstruct the first station and the second station to communicate witheach other in a third time period and the third station and the fourthstation to communicate with each other in a fourth time period, and thethird time period completely or partially overlaps the fourth timeperiod. The first station performs space-shared communication with thesecond station, the third station, and the fourth station based on thefourth instruction information.

In one embodiment, before operation S410, the first station may receivea channel quality measurement request frame sent by the AP, and thechannel quality measurement request frame is used to request the firststation, the second station, the third station, and the fourth stationto perform space sharing measurement. If the first station, the secondstation, the third station, and the fourth station agree to performspace sharing measurement, the first station, the second station, thethird station, and the fourth station reply with ACK frames afterreceiving the channel quality measurement request frame.

In one embodiment, the channel quality measurement request frame isfurther used to request a quantity of antenna modes determined by thefirst station and the second station through beamforming training. Afterreceiving the channel quality measurement request frame, the firststation may add, into an ACK frame sent to the AP, the quantity ofantenna modes determined by the first station and the second stationthrough beamforming training.

According to the communication method provided in this embodiment of thepresent invention, a success rate of space-shared communication betweenstation pairs can be increased. If a channel noise value measured by astation does not meet a threshold requirement, an antenna mode formeasurement and/or an antenna mode for communication are/is directlychanged based on the instruction sent by the access point, and channelquality measurement is continued. This reduces signaling overheads ofcommunication between the station and the access point, and reduces ameasurement time required for implementing space-shared communicationbetween station pairs.

FIG. 5 shows an apparatus 500 according to an embodiment of the presentinvention. The apparatus 500 may be, for example, an access point.

A first receiving unit 510 is configured to receive a first channelquality measurement report sent by a first station and a second channelquality measurement report sent by a second station, where the firstchannel quality measurement report indicates a channel noise valuemeasured in a first time period by the first station in a second antennamode when a third station and a fourth station communicate with eachother in a first antenna mode, and the second channel qualitymeasurement report indicates a channel noise value measured in the firsttime period by the second station in the second antenna mode when thethird station and the fourth station communicate with each other in thefirst antenna mode.

A first sending unit 520 is configured to send an grant frame if thechannel noise value measured by at least one of the first station andthe second station in the second antenna mode is greater than a firstthreshold, where the grant frame carries first instruction information,and the first instruction information is used to instruct to change thefirst antenna mode to an antenna mode other than the first antenna modeand/or to change the second antenna mode to an antenna mode other thanthe second antenna mode.

In one embodiment, the first instruction information is further used toindicate a second time period, and the first receiving unit 510 isfurther configured to receive a third channel quality measurement reportsent by the first station and a fourth channel quality measurementreport sent by the second station. The third channel quality measurementreport indicates a channel noise value measured in the second timeperiod by the first station in a current antenna mode when the thirdstation and the fourth station communicate with each other in a currentantenna mode, and the fourth channel quality measurement reportindicates a channel noise value measured in the second time period bythe second station in the current antenna mode when the third stationand the fourth station communicate with each other in the currentantenna mode. The first sending unit 520 is further configured to sendsecond instruction information if the channel noise values measured bythe first station and the second station in the current antenna mode areboth less than or equal to the first threshold. The second instructioninformation is used to indicate a third time period for the firststation and the second station to communicate with each other and afourth time period for the third station and the fourth station tocommunicate with each other, and the third time period completely orpartially overlaps the fourth time period, so that the first station,the second station, the third station, and the fourth station performspace-shared communication.

In one embodiment, the access point further includes a second sendingunit. The second sending unit is specifically configured to: send thirdinstruction information to the first station and the second stationamong a plurality of stations before the first channel qualitymeasurement report sent by the first station and the second station isreceived, where the third instruction information is used to instructthe first station and the second station to measure channel noise valuesin the first time period; and send fourth instruction information to thethird station and the fourth station among the plurality of stations,where the fourth instruction information is used to instruct the thirdstation and the fourth station to communicate with each other in thefirst time period.

In one embodiment, the third instruction information may be added into achannel quality measurement request frame, and the channel qualitymeasurement request frame is used to request to perform space sharingmeasurement.

In one embodiment, the channel quality measurement request frame isfurther used to request a quantity of antenna modes determined by thefirst station and the second station through beamforming training. Theaccess point further includes a second receiving unit, and the secondreceiving unit is specifically configured to receive channel qualitymeasurement acknowledgement frames sent by the first station and thesecond station. The channel quality measurement acknowledgement framecarries the quantity of antenna modes determined by the first stationand the second station through beamforming training.

According to the access point provided in this embodiment of the presentinvention, the first receiving unit receives the channel noise valuemeasured in the first time period by the first station in the secondantenna mode when the third station and the fourth station communicatewith each other in the first antenna mode and the channel noise valuemeasured in the first time period by the second station in the secondantenna mode when the third station and the fourth station communicatewith each other in the first antenna mode. The first sending unit sendsthe grant frame if the channel noise value received by at least one ofthe first station and the second station in the second antenna mode isgreater than the first threshold, where the grant frame carries thefirst instruction information, and the first instruction information isused to instruct to change the first antenna mode to an antenna modeother than the first antenna mode and/or to change the second antennamode to an antenna mode other than the second antenna mode. In this way,a success rate of space-shared communication between station pairs canbe increased.

According to the access point provided in this embodiment of the presentinvention, if a received channel noise value measured by a station doesnot meet a threshold requirement, the access point does not need to sendthe channel quality measurement request frame again, but directlyinstructs the station to change an antenna mode and continues channelquality measurement. This reduces signaling overheads of communicationbetween the station and the access point, and reduces a measurement timerequired for implementing space-shared communication between stationpairs.

FIG. 6 shows an apparatus 600 according to an embodiment of the presentinvention. The apparatus 600 may be, for example, a station.

A first sending unit 610 is configured to send a first channel qualitymeasurement report to an access point AP, where the first channelquality measurement report indicates a channel noise value measured in afirst time period by the apparatus 600 in a second antenna mode when athird station and a fourth station communicate with each other in afirst antenna mode.

A first receiving unit 620 is configured to receive an grant frame sentby the AP based on the first channel quality measurement report sent bythe first sending unit 610, where the grant frame carries firstinstruction information and/or second instruction information, the firstinstruction information is used to instruct the apparatus 600 and asecond station to measure channel noise values in an antenna mode otherthan the second antenna mode, and the second instruction information isused to instruct the apparatus 600 and the second station to communicatewith each other in an antenna mode other than the second antenna mode,so that the third station and the fourth station measure channel noisevalues.

In one embodiment, the grant frame further carries third instructioninformation used to indicate a second time period. The station furtherincludes a measurement unit, and the measurement unit is specificallyconfigured to measure, in the second time period based on the thirdinstruction information, a channel noise value in a third antenna modewhen the third station and the fourth station communicate with eachother in the first antenna mode. The first sending unit is specificallyconfigured to send a second channel quality measurement report to theAP, and the second channel quality measurement report is used toindicate the channel noise value measured in the second time period inthe third antenna mode when the third station and the fourth stationcommunicate with each other in the first antenna mode.

In one embodiment, after the second channel quality measurement reportis sent to the AP, the first receiving unit 620 is further configured toreceive fourth instruction information sent by the AP based on thesecond channel quality measurement report. The fourth instructioninformation is used to instruct the first station and the second stationto communicate with each other in a third time period and the thirdstation and the fourth station to communicate with each other in afourth time period, and the third time period completely or partiallyoverlaps the fourth time period. The station further includes acommunications unit, and the communications unit is specificallyconfigured to perform space-shared communication with the secondstation, the third station, and the fourth station based on the fourthinstruction information.

In one embodiment, the station further includes a second receiving unitand a second sending unit. The second receiving unit is specificallyconfigured to: before the first channel quality measurement report issent to the access point AP, receive a channel quality measurementrequest frame sent by the AP, where the channel quality measurementrequest frame is used to request a quantity of antenna modes determinedby the first station and the second station through beamformingtraining. The second sending unit is specifically configured to send achannel quality measurement acknowledgement frame to the AP after thechannel quality measurement request frame sent by the AP is received,where the channel quality measurement acknowledgement frame carries thequantity of antenna modes determined by the first station and the secondstation through beamforming training.

According to the station provided in this embodiment of the presentinvention, the channel noise value measured in the first time period bythe first station in the second antenna mode when the third station andthe fourth station communicate with each other in the first antenna modeand the channel noise value measured in the first time period by thesecond station in the second antenna mode when the third station and thefourth station communicate with each other in the first antenna mode,are received; and the grant frame is sent if the channel noise valuemeasured by at least one of the first station and the second station inthe second antenna mode is greater than the first threshold, where thegrant frame carries the first instruction information, and the firstinstruction information is used to instruct to change the first antennamode to an antenna mode other than the first antenna mode and/or tochange the second antenna mode to an antenna mode other than the secondantenna mode. In this way, a success rate of space-shared communicationbetween station pairs can be increased.

According to the station provided in this embodiment of the presentinvention, if the channel noise value measured by the station does notmeet a threshold requirement, an antenna mode for measurement and/or anantenna mode for communication are/is directly changed based on theinstruction sent by the access point, and channel quality measurement iscontinued. This reduces signaling overheads of communication with accesspoint, and reduces a measurement time required for implementingspace-shared communication between station pairs.

FIG. 7 shows an apparatus 700 according to an embodiment of the presentinvention. The apparatus 700 includes a processor 710, a transmitter720, a receiver 730, a memory 740, and a bus system 750. The processor710, the transmitter 720, the receiver 730, and the memory 740 areconnected by the bus system 750. The memory 740 is configured to storean instruction, and the processor 710 is configured to execute theinstruction stored in the memory 740, to control the transmitter 720 tosend a signal. The transmitter 720 and the receiver 730 may becommunication interfaces. Specifically, the transmitter 720 may be aninterface configured to receive data and/or an instruction, and thereceiver 730 may be an interface configured to send data and/or aninstruction. Specific forms of the transmitter 720 and the receiver 730are not described using examples herein.

It should be understood that the apparatus 700 may be an access point,and may be configured to perform the corresponding steps and/orprocedures in the foregoing method embodiments. Optionally, the memory740 may include a read-only memory and a random access memory, andprovide an instruction and data to the processor. A part of the memorymay further include a non-volatile random access memory. For example,the memory may further store device type information. The processor 710may be configured to execute the instruction stored in the memory. Whenthe processor executes the instruction, the processor may perform thesteps corresponding to an access point that are in the foregoing methodembodiments.

FIG. 8 shows an apparatus 800 according to an embodiment of the presentinvention. The apparatus 800 includes a processor 810, a transmitter820, a receiver 830, a memory 840, and a bus system 850. The processor810, the transmitter 820, the receiver 830, and the memory 840 areconnected by the bus system 850. The memory 840 is configured to storean instruction, and the processor 810 is configured to execute theinstruction stored in the memory 840, to control the transmitter 820 tosend a signal. The transmitter 820 and the receiver 830 may becommunication interfaces. Specifically, the transmitter 820 may be aninterface configured to receive data and/or an instruction, and thereceiver 830 may be an interface configured to send data and/or aninstruction. Specific forms of the transmitter 820 and the receiver 830are not described using examples herein.

It should be understood that the apparatus 800 may be a station, and maybe configured to perform the corresponding steps and/or procedures inthe foregoing method embodiments. Optionally, the memory 840 may includea read-only memory and a random access memory, and provide aninstruction and data to the processor. A part of the memory may furtherinclude a non-volatile random access memory. For example, the memory mayfurther store device type information. The processor 810 may beconfigured to execute the instruction stored in the memory. When theprocessor executes the instruction, the processor may perform the stepscorresponding to a station that are in the foregoing method embodiments.

It should be understood that in this embodiment of the presentinvention, the processor may be a central processing unit (CentralProcessing Unit, CPU), or the processor may be another general-purposeprocessor, a digital signal processor (DSP), an application-specificintegrated circuit (ASIC), a field programmable gate array (FPGA) oranother programmable logic device, a discrete gate or transistor logicdevice, a discrete hardware component, or the like. The general-purposeprocessor may be a microprocessor, or the processor may be anyconventional processor or the like.

In an implementation process, steps in the foregoing methods may becompleted by using a hardware integrated logic circuit in the processor,or by using instructions in a form of software. The steps of the methodsdisclosed with reference to the embodiments of the present invention maybe directly performed by a hardware processor, or may be performed byusing a combination of hardware in the processor and a software module.The software module may be located in a mature storage medium in theart, such as a random access memory, a flash memory, a read-only memory,a programmable read-only memory, an electrically erasable programmablememory, or a register. The storage medium is located in the memory, anda processor executes an instruction in the memory and completes thesteps in the foregoing methods in combination with the hardware in theprocessor. To avoid repetition, details are not described herein again.

A person of ordinary skill in the art may be aware that the method stepsand units described with reference to the embodiments disclosed in thisspecification may be implemented by electronic hardware, computersoftware, or a combination thereof. To clearly describe theinterchangeability between hardware and software, the foregoing hasgenerally described the steps and compositions of the embodiments basedon functions. Whether the functions are implemented by hardware orsoftware depends on particular applications and design constraintconditions of the technical solutions. A person of ordinary skill in theart may use a different method to implement the described functions foreach particular application, but it should not be considered that theimplementation goes beyond the scope of this application.

It may be clearly understood by a person skilled in the art that, forthe purpose of convenient and brief description, for a detailed workingprocess of the foregoing system, apparatus, and unit, reference may bemade to a corresponding process in the foregoing method embodiments, anddetails are not described again.

In the several embodiments provided in this application, it should beunderstood that the disclosed system, apparatus, and method may beimplemented in other manners. For example, the described apparatusembodiments are merely examples. For example, the unit division ismerely logical function division and may be other division in actualimplementation. For example, a plurality of units or components may becombined or integrated into another system, or some features may beignored or not performed. In addition, the displayed or discussed mutualcouplings or direct couplings or communication connections may beindirect couplings or communication connections via some interfaces,apparatuses, or units, or may be electrical connections, mechanicalconnections, or connections in other forms.

The units described as separate parts may or may not be physicallyseparate. Parts displayed as units may or may not be physical units, andmay be located in one position or distributed on a plurality of networkunits. Some or all of the units may be selected based on actual needs toachieve the objectives of the solutions of the embodiments of thepresent invention.

In addition, functional units in the embodiments of this application maybe integrated into one processing unit, or each of the units may existalone physically, or two or more units may be integrated into one unit.The integrated unit may be implemented in a form of hardware, or may beimplemented in a form of a software functional unit.

When the integrated unit is implemented in the form of a softwarefunctional unit and sold or used as an independent product, theintegrated unit may be stored in a computer-readable storage medium.Based on such an understanding, the technical solutions of thisapplication essentially, or the part contributing to the prior art, orall or a part of the technical solutions may be implemented in the formof a software product. The computer software product is stored in astorage medium and includes several instructions for instructing acomputer device (which may be a personal computer, a server, a networkdevice, or the like) to perform all or some of the steps of the methodsdescribed in the embodiments of the present invention. The foregoingstorage medium includes any medium that can store program code, such asa USB flash drive, a removable hard disk, a read-only memory (Read-OnlyMemory, “ROM” for short), a random access memory (Random Access Memory,“RAM” for short), a magnetic disk, or an optical disc.

The foregoing descriptions are merely specific embodiments of thisapplication, but are not intended to limit the protection scope of thisapplication. Any modification or replacement readily figured out by aperson skilled in the art within the technical scope disclosed in thepresent invention shall fall within the protection scope of thisapplication. Therefore, the protection scope of this application shallbe subject to the protection scope of the claims.

What is claimed is:
 1. An access point, comprising: a first receivingunit configured to receive a first channel quality measurement reportfrom a first station and a second channel quality measurement reportfrom a second station, wherein the first channel quality measurementreport indicates a first channel noise value measured during a firsttime period by the first station in a second antenna mode when a thirdstation and a fourth station communicate with each other in a firstantenna mode, and wherein the second channel quality measurement reportindicates a second channel noise value measured during the first timeperiod by the second station in the second antenna mode when the thirdstation and the fourth station communicate with each other in the firstantenna mode; and a first sending unit configured to send an grant frameif at least one of the first and second channel noise values received bythe first receiving unit and measured by at least one of the firststation and the second station in the second antenna mode is greaterthan a first threshold, wherein the grant frame includes firstinstruction information used to instruct to change the first antennamode to an antenna mode other than the first antenna mode and/or tochange the second antenna mode to an antenna mode other than the secondantenna mode.
 2. The access point according to claim 1, wherein thefirst instruction information is further used to indicate a second timeperiod, and the first receiving unit is further configured to receive athird channel quality measurement report from the first station and afourth channel quality measurement report from the second station,wherein the third channel quality measurement report indicates a thirdchannel noise value measured during the second time period by the firststation in a current antenna mode when the third station and the fourthstation communicate with each other in a current antenna mode, and thefourth channel quality measurement report indicates a fourth channelnoise value measured during the second time period by the second stationin the current antenna mode when the third station and the fourthstation communicate with each other in the current antenna mode; and thefirst sending unit is further configured to send second instructioninformation if the third and fourth channel noise values measured by thefirst station and the second station respectively in the current antennamode are both less than or equal to the first threshold, wherein thesecond instruction information is used to indicate a third time periodfor the first station and the second station to communicate with eachother and a fourth time period for the third station and the fourthstation to communicate with each other, and the third time periodcompletely or partially overlaps the fourth time period, so that thefirst station, the second station, the third station, and the fourthstation perform space-shared communication.
 3. The access pointaccording to claim 1, wherein the access point further comprises asecond sending unit, wherein the second sending unit is configured tosend third instruction information to the first station and the secondstation among a plurality of stations before the first channel qualitymeasurement report sent by the first station and the second station isreceived, wherein the third instruction information is used to instructthe first station and the second station to measure channel noise valuesduring the first time period; and send fourth instruction information tothe third station and the fourth station among the plurality ofstations, wherein the fourth instruction information is used to instructthe third station and the fourth station to communicate with each otherduring the first time period.
 4. The access point according to claim 3,wherein the third instruction information is carried in a channelquality measurement request frame, and the channel quality measurementrequest frame is used to request to perform space sharing measurement.5. The access point according to claim 4, wherein the channel qualitymeasurement request frame is further used to request a quantity ofantenna modes determined by the first station and the second stationamong the plurality of stations through beamforming training; andwherein the access point further comprises a second receiving unitconfigured to receive channel quality measurement acknowledgement framesfrom the first station and the second station, wherein each of thechannel quality measurement acknowledgement frames includes the quantityof antenna modes determined by the first station and the second stationrespectively through beamforming training.
 6. A station, comprising: afirst sending unit configured to send a first channel qualitymeasurement report to an access point (AP), wherein the first channelquality measurement report indicates a channel noise value measuredduring a first time period by the station in a second antenna mode whena third station and a fourth station communicate with each other in afirst antenna mode; and a first receiving unit configured to receive angrant frame from the AP in response to the first channel qualitymeasurement report sent by the first sending unit, wherein the grantframe includes first instruction information and/or second instructioninformation, the first instruction information is used to instruct thestation and the second station to measure channel noise values in anantenna mode other than the second antenna mode, and the secondinstruction information is used to instruct the station and the secondstation to communicate with each other in an antenna mode other than thesecond antenna mode, so that the third station and the fourth stationmeasure channel noise values.
 7. The station according to claim 6,wherein the grant frame further includes third instruction informationused to indicate a second time period, and the station further comprisesa measurement unit, wherein the measurement unit is configured tomeasure, based on the third instruction information, a channel noisevalue during the second time period in a third antenna mode when thethird station and the fourth station communicate with each other in thefirst antenna mode; and the first sending unit is configured to send asecond channel quality measurement report to the AP, wherein the secondchannel quality measurement report is used to indicate the channel noisevalue measured during the second time period in the third antenna modewhen the third station and the fourth station communicate with eachother in the first antenna mode.
 8. The station according to claim 7,wherein the first receiving unit is further configured to: after thesecond channel quality measurement report is sent to the AP, receivefourth instruction information from the AP in response to the secondchannel quality measurement report, wherein the fourth instructioninformation is used to instruct the station and the second station tocommunicate with each other during a third time period and the thirdstation and the fourth station to communicate with each other during afourth time period, and the third time period completely or partiallyoverlaps with the fourth time period; and the station further comprisesa communications unit, wherein the communications unit is configured toperform space-shared communication with the second station, the thirdstation, and the fourth station based on the fourth instructioninformation.
 9. The station according to claim 6, wherein the stationfurther comprises a second receiving unit and a second sending unit,wherein the second receiving unit is configured to: before the firstchannel quality measurement report is sent to the AP, receive a channelquality measurement request frame from the AP, wherein the channelquality measurement request frame is used to request a quantity ofantenna modes determined by the station and the second station throughbeamforming training; and the second sending unit is configured to senda channel quality measurement acknowledgement frame to the AP after thechannel quality measurement request frame is received from the AP,wherein the channel quality measurement acknowledgement frame includesthe quantity of antenna modes determined by the station and the secondstation through beamforming training.
 10. A communication method,comprising: sending, by a first station, a first channel qualitymeasurement report to an access point (AP), wherein the first channelquality measurement report includes a channel noise value measuredduring a first time period by the first station in a second antenna modewhen a third station and a fourth station communicate with each other ina first antenna mode; and receiving, by the first station, an grantframe from the AP in response to the first channel quality measurementreport, wherein the grant frame includes first instruction informationand/or second instruction information, the first instruction informationis used to instruct the first station and the second station to measurechannel noise values in an antenna mode other than the second antennamode, and the second instruction information is used to instruct thefirst station and the second station to communicate with each other inan antenna mode other than the second antenna mode, so that the thirdstation and the fourth station measure channel noise values.
 11. Themethod according to claim 10, wherein the grant frame further includesthird instruction information used to indicate a second time period, andthe method further comprises: measuring, by the first station based onthe third instruction information, a channel noise value during thesecond time period in a third antenna mode when the third station andthe fourth station communicate with each other in the first antennamode; and sending, by the first station, a second channel qualitymeasurement report to the AP, wherein the second channel qualitymeasurement report is used to indicate the channel noise value measuredwithin the second time period in the third antenna mode when the thirdstation and the fourth station communicate with each other in the firstantenna mode.
 12. The method according to claim 11, wherein after thesending a second channel quality measurement report to the AP, themethod further comprises: receiving, by the first station, fourthinstruction information from the AP in response to the second channelquality measurement report, wherein the fourth instruction informationis used to instruct the first station and the second station tocommunicate with each other within a third time period and the thirdstation and the fourth station to communicate with each other within afourth time period, and the third time period completely or partiallyoverlaps the fourth time period; and performing, by the first station,space-shared communication with the second station, the third station,and the fourth station based on the fourth instruction information. 13.The method according to claim 10, wherein before the sending, by a firststation, a first channel quality measurement report to the AP, themethod further comprises: receiving, by the first station, a channelquality measurement request frame from the AP, wherein the channelquality measurement request frame is used to request a quantity ofantenna modes determined by the first station and the second stationthrough beamforming training; and sending, by the first station, achannel quality measurement acknowledgement frame to the AP, wherein thechannel quality measurement acknowledgement frame includes the quantityof antenna modes determined by the first station and the second stationthrough beamforming training.